Method and apparatus for lancet launching device integrated onto a blood-sampling cartridge

ABSTRACT

A method and apparatus ( 2 ) for obtaining a sample of blood. An embodiment includes an apparatus ( 2 ) which integrates lancing ( 12 ), sample collection, and analysis. The presence of patients finger on the active sampling area can be sensed by monitoring the pressure applied by the finger on the device ( 2 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 10/363,510 filedSep. 29, 2003 (now U.S. Pat. No. 7,749,174), which is a §3.71 filing ofPCT/US02/19060 filed Jun 12, 2002, which in turn claims the benefit ofU.S. Ser. No. 60/297,860 filed Jun 12, 2001; which also claims thebenefit of the parent case of U.S. Ser. No. 10/127,201 U.S. Pat. No.7,041,068). All applications above are fully incorporated herein byreference.

TECHNICAL FIELD

Lancing devices are well known in the medical health-care productsindustry for piercing the skin to produce blood for analysis.Biochemical analysis of blood samples is a diagnostic tool fordetermining clinical information. Many point-of-care tests are performedusing capillary whole blood, the most common being monitoring bloodglucose level in diabetics. Typically, a drop of blood is obtained bymaking a small incision in the fingertip, creating a small wound, whichgenerates a small blood droplet on the surface of the skin.

BACKGROUND ART

Early methods of lancing included piercing or slicing the skin with aneedle or razor. Current methods utilize lancet drivers that contain amultitude of spring, cam and mass actuators to drive the lancet. Theseinclude cantilever springs, diaphragms, coil springs, as well as gravityplumbs to actuate the lancet. Typically, the device is pre-cocked, orthe user cocks the device. The device is held against the skin and theuser mechanically triggers the ballistic launch of the lancet.

The problem with current devices is that they require two hands tooperate, one to hold the device and push a button which activates thedevice, and the other hand to provide a finger for lancing. Afterlancing, the finger needs to be free to move to another device forcollection of the blood droplet and subsequent analysis.

Generally, known methods of blood sampling require several steps. First,a measurement session is set up by gathering various paraphernalia suchas lancets, launchers, test strips, instrument, etc. Second, the patientmust assemble the paraphernalia by loading a sterile lancet, loading atest strip, and arming the launcher.

Third, the patient must place their finger against the lancet launcherand using the other hand activate the launcher. Fourth, the patient mustput down the launcher and place the bleeding finger against a teststrip, which may or may not have been loaded into the instrument. Thepatient must insure blood has been loaded onto the test strip and theinstrument has been calibrated prior to such loading. Finally, thepatient must dispose of all the blood contaminated paraphernaliaincluding the lancet. What has been needed is a blood sampling deviceand method that simplifies the blood sampling procedure.

DISCLOSURE OF INVENTION

Embodiments of the present invention are related to medical health-careproducts and to methods for obtaining blood for chemical analysis. Moreparticularly, embodiments of the invention relate to devices and methodsfor piercing the skin (lancing) with a sensor to detect the presence ofa patient's finger and activate the lancet automatically. In someembodiments, the cartridge and lancet are disposable.

In accordance with embodiments of the invention, a patient will be ableto obtain a sample of blood in an ergonomic, convenient way using amethod and apparatus which integrates lancing, sample collection, andanalysis. The presence of patients finger on the ergonomic sampling areais sensed by monitoring the pressure applied by the finger on thecartridge which houses the lancet. The application of a predeterminedpressure is measured by a piezoelectric or electrical circuit.

Advantages can be achieved in a blood sampling device by integrating thelancing and blood sample collection procedure so that the device cancapture and transport the capillary blood from the wound created by thelancet to a desired active area, such as a strip for analyzing glucose.This can be done in embodiments of the invention by integrating thelancet, conduit and reservoir into a disposable cartridge which can beinserted into a hand-held sampling device with instrumentation foranalyzing the blood sample.

In the use of an embodiment of the invention, a finger is placed over anergonomically contoured sampling area and pressure is applied with thefinger so that a sensor will activate the lancet, which will, in turn,lance the finger and allow the blood sample to be collected in theconduit and transported to the reservoir for analysis in a single stepfrom the patient's perspective.

BRIEF DESCRIPTION OF DRAWING

The objects, advantages and features of this invention will be morereadily appreciated from the following detailed description, when readin conjunction with the accompanying drawing, in which:

FIG. 1 is a drawing of the cartridge which houses the lancet.

FIG. 2 is a drawing of the chamber in the sampling device where thecartridge is loaded.

FIG. 3 is a drawing of the cartridge loaded into the sampling device.

FIG. 4 is a drawing of an alternate lancet configuration.

FIG. 5 is a drawing of the orifice and ergonomically contoured samplingarea.

FIG. 6 is a drawing of the lancing event.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made to embodiments of the invention, examples ofwhich are illustrated in the accompanying drawings. Wherever possible,the same reference numbers will be used throughout the drawings to referto the same or like parts.

FIG. 1 shows the disposable cartridge (10) which houses the lancet (12).

Disposable means that the cartridge is used for one lancing cycle and isthen discarded.

The lancet (12) has a distal end (16) which connects to the driver (40)and a proximal end (14) which lances the skin. The proximal end (14) isembedded within the conduit (18). Embedded means completely shielded bythe cartridge when it is not lancing. The distal end (16) extends intothe cavity (20). The reservoir (22) has a narrow opening (24) on theergonomically contoured surface (26) which is adjacent to the proximalend (14) of the lancet (12). The term ergonomically contoured isgenerally defined to mean shaped to snugly fit a finger placed on thesurface. The term reservoir is generally defined to mean an area whichallows pooling of the blood sample. The term narrow is generally definedto mean a reduction in diameter of the reservoir so as to exploitcapillary forces to better channel the blood into the rest of thereservoir. The term adjacent, as used in the context of the proximity ofthe proximal end (16) and narrow opening (24), is generally defined tomean that the proximal end (16) and the narrow opening (24) are locatedin the same general area. The cartridge (10) is capable of channelingthe blood sample, which means transporting through small passages (notshown), to an active area (28) which corresponds to the device's systemfor analyzing the blood. This system can consist of a chemical,physical, optical, electrical or other means of analyzing the bloodsample. The lancet and reservoir embodiment illustrated are integratedinto the cartridge in a single packaged unit.

FIG. 2 shows the chamber (30) in the sampling device where the cartridgeis loaded. The cartridge is loaded on a socket (32) suspended withsprings (34) and sits in slot (36). The launcher (38) is attached to thesocket (32). The launcher has a proximal end (40) and a distal end (42).The launcher is any mechanical (such as spring or cam driven) orelectrical (such as electromagnetically or electronically driven) meansfor advancing, stopping, and retracting the lancet. There is a clearance(44) between the distal end of the launcher (42) and the sensor (46)which is attached to the chamber (30). The socket (32) also contains thesystem for analyzing the blood (48) which corresponds to the active area(28) on the cartridge (10) when it is loaded into the socket (32).

FIG. 3 shows a cartridge (10) loaded into the socket (32). The activearea (28) and system for analyzing the blood (48) overlap. The launcher(38) fits into the cavity (20). The proximal end (40) of the launcher(38) abuts the distal end (16) of the lancet (12). The patient's finger(50) sits on the ergonomically contoured surface (26).

FIG. 4 shows a drawing of an alternate lancet configuration where thelancet (12) and launcher (38) are oriented to lance the side of thefinger (50) as it sits on the ergonomically contoured surface (26).

FIG. 5 illustrates with exploded detail the orifice (52) andergonomically contoured surface (26). The conduit (18) has an orifice(52) which opens on a blood well (54). The narrow opening (24) of thereservoir (22) also opens on the blood well (54). The diameter of thenarrow opening (24) is significantly greater than the diameter of theorifice (52) which is substantially the same diameter as the diameter ofthe lancet (12). After the lancet is retracted, the blood flowing fromthe finger (50) will collect in the blood well (54). The lancet (12)will have been retracted into the orifice (52) effectively blocking thepassage of blood down the orifice (52). The blood will flow from theblood well (54) through the narrow opening (24) into the reservoir (22).

FIG. 6 shows a drawing of the lancing event. The patient appliespressure by pushing down with the finger (50) on the ergonomicallycontoured surface (26). This applies downward pressure on the cartridge(10) which is loaded into the socket (32).

As the socket (32) is pushed downward it compresses the springs (34).The sensor (46) makes contact with the distal end (42) of the launcher(38) and thereby detects the presence of the finger on the ergonomicallycontoured surface. Detection means sensing using electrical means. Thesensor is a piezoelectric device which detects this pressure and sends asignal to circuit (56) which actuates the launcher (38) and advances andthen retracts the lancet (12) lancing the finger (50). In anotherembodiment, the sensor (46) is an electric contact which closes acircuit when it contacts the launcher (38) activating the launcher (38)to advance and retract the lancet (12) lancing the finger (50).

Activating means beginning the lancing event, which consists ofadvancing, stopping, and retracting the lancet.

An embodiment of the invention is a method of sampling which reduces thenumber of steps that must be taken by a patient to obtain a sample andanalysis of the sample. First, the patient loads a cartridge with anembedded sterile lancet into the device. Second, the patient initiates alancing cycle by turning on the power to the device or by placing thefinger to be lanced on the ergonomically contoured surface and pressingdown. Initiation means arming the device. This initiation prompts thesensor.

Prompting means that the sensor is made operational and given control toactivate the launcher. Prompting is a safety precaution to avoidunintentionally launching the lancet.

The sensor is unprompted when the lancet is retracted after its lancingcycle to avoid multiple lancing events that would cause unnecessary painand obstruct the collection of the blood sample. The lancing cycleconsists of arming, advancing, stopping and retracting the lancet, andcollecting the blood sample in the reservoir. The cycle is complete oncethe blood sample has been collected in the reservoir. Third, the patientpresses down on the cartridge which forces the launcher to make contactwith the sensor and activates the launcher. The lancet then pierces theskin and the reservoir collects the blood sample. The patient is thenoptionally informed to remove the finger by an audible signal such as abuzzer or a beeper, and/or a visual signal such as an LED or a displayscreen. The patient can then dispose of all the contaminated parts byremoving the cartridge and disposing of it. In another embodiment,multiple cartridges may be loaded into the sampling device in the formof a cassette. The patient is informed by the device as to when todispose of the entire cassette after the analysis is complete.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein.

It is intended that the specification and examples be considered asexemplary only, with a true scope and spirit of the invention beingindicated by the following claims.

1. A body fluid sampling system for use on a tissue site, comprising: adrive force generator; a housing with at least a proximal portion and adistal portion, the proximal portion being a handle portion configuredto be held by a user, at least a portion of the distal portion having anergonomically contoured surface adapted to conform to a tip of a finger;a plurality of sample chambers and a plurality of penetrating membersoperatively couplable to the drive force generator, each of a samplechamber being associated with a penetrating member; a disposable thathouses the plurality of sample chambers and the plurality of penetratingmembers, the disposable being positioned in the distal portion of thehousing; a penetrating member sensor positioned to monitor thepenetrating member coupled to the force generator, the penetratingmember sensor configured to provide information relative to a depth ofthe penetrating member through a skin surface; and wherein thepenetrating member sensor is further configured to provide an indicationof velocity of the penetrating member.
 2. The system of claim 1, whereinthe ergonomically contoured surface is shaped to snugly fit the tip ofthe finger.
 3. The system of claim 1, further comprising: a user controlpad coupled to the housing.
 4. The system of claim 3, wherein the usercontrol pad has a plurality of function keys.
 5. The system of claim 4,wherein at least one of a user's hand digits can access the functionkeys.
 6. The system of claim 4, wherein the plurality of function keysare arranged in a circular geometry.
 7. The system of claim 4, whereinthe function keys are arranged as direction arrows in a circulargeometry.
 8. The system of claim 4, wherein the function keys include acenter function key with function keys in a surrounding relationship tothe center function key to provide for up, down, left and rightmovement.
 9. The system of claim 3, wherein the user uses the controlpad to provide for up, down, left, right, center and then presses enter.10. The system of claim 1, wherein, each of a sample chamber has avolume of no greater than 1 microliter.
 11. The system of claim 1,wherein the disposable has a geometry selected from at least one of adrum, disk, magazine and bandolier.
 12. The system of claim 1, whereinthe disposal is rotatable within the distal portion of the housing. 13.The system of claim 1, further comprising: a flexible support membercoupling the penetrating members and configured to move each of thepenetrating members to a launch position associated with the forcegenerator.
 14. The system of claim 1, wherein the active penetratingmember is launched from the housing along a substantially linear pathinto the tissue.
 15. The system of claim 1, wherein the activepenetrating member moves along an at least partially curved path intothe tissue.
 16. The system of claim 1, wherein the driver is a voicecoil drive force generator.
 17. The system of claim 1, wherein thedriver is a rotary voice coil drive force generator.
 18. The system ofclaim 1, further comprising: a processor, wherein the processor includesa memory for storage and retrieval of a set of penetrating memberprofiles utilized with the penetrating member driver.
 19. The system ofclaim 1, wherein in a first direction into the tissue the penetratingmember moves toward the target tissue at a first speed and withdraws outof the tissue at a second speed.
 20. The system of claim 19, wherein thefirst and second speeds are the same.
 21. The system of claim 19,wherein the first speed is greater than the second speed.
 22. The systemof claim 19, wherein the first speed is about 2.0 to 10.0 m/sec.
 23. Thesystem of claim 19, wherein the first speed is about 0.05 to 60 m/sec.24. The system of claim 19, wherein the first speed is about 0.1 to 20.0m/sec.
 25. The system of claim 19, wherein the first speed is about 1.0to 10.0 m/sec.
 26. The system of claim 19, wherein the first speed isabout 3.0 to 8.0 m/sec.
 27. The system of claim 1, wherein a dwell timeof the penetrating member in the target tissue below a skin surface isin the range of 1 microsecond to 2 seconds.
 28. The system of claim 1,wherein a dwell time of the penetrating member in the target tissuebelow a skin surface is in the range of 500 milliseconds to 1.5 second.29. The system of claim 1, wherein a dwell time of the penetratingmember in the target tissue below a skin surface is in the range of 100milliseconds to 1 second.